The move comes after OFT research showed small businesses had low awareness of recent legislation such as the Competition Act, which gives the OFT greater power to clamp down on cartels and companies with abusive market dominance.
The research, carried out last year, revealed firms with more than 200 employees had a much greater knowledge of competition law.
OFT director of comms Mike Ricketts said: ‘We need to show that competition brings choice for the consumer and that variety of choice and price brings satisfied customers.
‘We are going to promote the benefits of open markets and the disadvantages of markets driven by cartels or monopolies,’ he added.
OFT head of publicity and marketing Sue Cook said SMEs were difficult to reach because of their sheer numbers.
The campaign will launch in spring next year. Fees are believed to be around £100,000. Meanwhile, the OFT launched a one-month campaign this week to educate the public on mass-marketed scams that are received via unsolicited email, post or phone calls.
Every week in February will see announcements on different types of scams and advice on how consumers can protect themselves.
Leaflets are also being distributed through councils, Neighbourhood Watch schemes and charities.
There is also a radio ad campaign and media relations activity.